What makes a successful e-car?

Zero emissions, and a top speed of 125 miles per hour, all without a drop of gasoline. This is not your father's electric car; this is the "Tesla Model S." And beginning today, you can have one, starting at less than $500 a month, according to Elon Musk, CEO of the Tesla Motors.

Musk is the billionaire personally backing the deal for the "Tesla Model S," which can cost north of $70,000. The company is finally making money with the car, posting its first profit this quarter since going public in 2010.

Meanwhile, electronic car company Fisker is eyeing bankruptcy. What is Tesla doing right, that Fisker is doing wrong?

While Tesla has produced a well-designed car from an aesthetic standpoint, says Musk, the company's focus has been on engineering.

"We're really a hard-core engineering company, and a hard-core manufacturing company," said Musk, unlike Fisker.

"Henrik Fisker was essentially a stylist," said Musk. "He was good at ... figuring out the aesthetic design of a car, but not at figuring out how to make it work."

Fisker had a lot of severe quality problems, added the Tesla CEO.

"They had this issue where the cars would spontaneously combust, and obviously that's not a good thing."

Watch The Lead with Jake Tapper at 4pm ET on CNN for the full interview.